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Earth History Illustrations

Turseodus dolorensis, a 6" long, carnivorous fish passes above two Tanytrachelos, small, aquatic reptiles prepared to hide within the detritus of a warm, freshwater pond. The scene is in Petrified Forest National Park in Arizona during the Triassic, some 225 million years ago. The accumulated leaves of ferns, cycad-like plants, horsetails, conifers and algae represent some of the flora of the Chinle Formation, extensive Triassic deposits of brightly colored stream sediments that today cover much of the southwest United States.

The fossil remains which place Tanytrachelos in Petrified Forest are so fragmentary that they might not be correctly identified. Tanytrachelos is well represented in Triassic freshwater deposits from the eastern United States.